tbuckley/cabot-search huggingface dataset:
Abstract P1012: Tbx18 Drives Nodal-like Self-assembly Of Pacemaker Myocytes And Non-myocytes
Authors: Jinqi Fan, Tae Y Kim, David Wolfson, Hee Cheol C Cho
Journal: Circulation Research (2022)

Background: We have demonstrated that TBX18 suffices to reprogram postnatal ventricular cardiomyocytes (CMs) to induced pacemaker cells. Cell-cell interactions and cell-extracellular matrix (ECM) are important regulators of microtissue organization and assembly. Here, we sought to gain a finer understanding of self-organization and assembly of pacemaker microtissue with myocytes and non-myocytes driven by TBX18. Methods: 2D monolayer of neonatal rat ventricular myocytes (NRVMs) were transduced with Adeno- GFP and Adeno-TBX18 in vitro model. AAV9-TBX18 was delivered via tail vein injection of Hcn4 (+/eGFP) transgenic mice to track the induced pacemaker myocytes. Result: TBX18-NRVMs showed more compact nodal-like aggregates with a higher density of CMs and surrounded by nonmyocytes. The number of alpha smooth muscle actin (αSMA) + myofibroblasts producing specific ECM and facilitating cell motility was increased by 190% in TBX18-NRVMs as well. Systemic delivery of AAV9-TBX18 via tail vein of mice created aggregation of de novo Hcn4+ induced pacemaker myocytes (iPMs) surrounded by αSMA+ myofibroblasts in vivo. Then, we treated pre-plated neonatal rat ventricular cells (NRVCs, including CMs and nonmyocytes) to explore the potential role of cell-cell communication and cell-ECM interaction in the formation of nodal-like aggregates through scRNA-seq. The data indicated that TBX18+ CM (28.6% % of all CMs) and TBX18-negative CMs (71.4% of all CMs) presented highly consistent transcriptomic profiles at day 3. No significant difference in Hcn4 transcript levels and the ratio of iPMs (defined as Hcn4+, Gja1 low , Nkx2.5 low , Tnni3 high , Actn2 high CM) was observed between them, as well as other pacemaker genes, suggesting cross-communication between them. Despite of TBX18+ fibroblasts (FBs) accounting for only 5% of all FBs, a higher proportion of activated myofibroblasts (39.3% vs. 25.4%) and lower proportion of quiescent FBs were observed in TBX18-NRVCs compared to control. Enrichment analysis revealed that TBX18-CMs lost ventricular specific electrical coupling and sarcomere organization (down-regulated Gja1, Cdh2, Irx3 ), but reconstructed hemidesmosome assembly and cell-ECM interaction enriched in sinoatrial node myocytes (Upregulated Lamc1, Itgb1, Plec, Des, Actn1, and Acta2 ) and activated Tgfβ signaling. Furthermore, treatment with gap junction inhibitor palmitoleic acid as well as Tgfβ receptor inhibitor A83-01 significantly suppressed the activation of quiescent fibroblasts to αSMA+ myofibroblasts and the formation of nodal-like aggregation of TBX18-NRVMs. Conclusion: TBX18 drives self-organization and nodal-like assembly of pacemaker microtissue with myocytes and non-myocytes through cell-cell communication of gap junction and Tgfβ signal.
Abstract P2082: Igfbp-3 Activates Pro-survival Pathways To Mitigate Anthracycline-induced Cardiomyocyte Injury
Authors: Junjie Chen, Jerome Awada, Jeremy Jong, Rene R Packard
Journal: Circulation Research (2022)

Rationale: Anthracyclines such as doxorubicin are among the most effective chemotherapeutic agents; however, their use leads to frequent cardiovascular complications, including heart failure, due to the activation of multiple cardiomyocyte injury pathways. Insulin-like growth factor binding protein-3 (IGFBP3) is strongly upregulated in cardiomyocytes after administration of doxorubicin. However, its role in doxorubicin-induced cardiomyocyte apoptosis and survival remains controversial. Methods and Results: We demonstrate that IGFBP3 is strongly induced by doxorubicin in neonatal ventricular myocytes (NRVMs) 12 hours after doxorubicin treatment by RT-PCR (4.2 fold vs. control, n=3, P&lt;0.05) and Western blot. Adenoviral overexpression of IGFBP3 in NRVMs leads to a significant reduction of phosphorylated H2A histone (γH2AX) after doxorubicin treatment, a hallmark of DNA double-strand breaks (DSBs), as well as topoisomerase IIβ, a key mediator of doxorubicin induced DNA DSBs. Conversely, silencing of IGFBP3 with siRNA leads to a significant increase of γH2AX expression in NRVMs. Adenoviral shRNA silencing of IGFBP3 in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) further demonstrates a 44% and 52% decrease in contraction magnitude and velocity in response to doxorubicin compared with scramble shRNA (scramble shRNA, n=5, shIGFBP3, n=3, P&lt;0.05). Immunofluorescent imaging and cell fractionation assays conducted in NRVMs indicate that doxorubicin initiates IGFBP3 nuclear translocation, suggesting an active role in the cardiomyocyte response to doxorubicin-induced cell injury. Next generation sequencing of hiPSC-CMs treated with doxorubicin reveals that overexpression of IGFBP3 leads to upregulation of cardiomyocyte survival pathways, including TNF receptors without cytoplasmic death domain (TNFRSF10C and D), BCL2 family gene BCL2L1, the p53 target ACER2, the p53 co-factor FBXW7, the β-catenin mediator TBX3 and the ataxia telangiectasia mutated (ATM) activator ZNF423. Conclusion: Our findings indicate that IGFBP3 is strongly induced in cardiomyocytes by doxorubicin treatment. Overexpression of IGFBP3 attenuates doxorubicin induced DNA DSBs and promotes pro-survival signaling pathways.
Abstract P2008: Hypertrophic Cardiomyopathy Treatment Using Ultrasound And Microbubbles
Authors: Davindra Singh, Stephanie He, Brandon Helfield
Journal: Circulation Research (2022)

Introduction: Hypertrophic cardiomyopathy is a disease characterized by the abnormal growth of cardiomyocytes (CMs), a marker of which is the early downregulation of miR-1. The delivery of miR-1 to hypertrophic CMs presents as a promising treatment strategy, however there are still limitations in the safe and efficient delivery of gene therapeutics.Ultrasound (US) and microbubbles is an emerging approach to site-specific gene delivery. Microbubbles have long been employed in clinical cardiology as a diagnostic contrast agent. Recent work has demonstrated that under specific conditions, they are capable of forming temporary pores on neighboring cell membranes, allowing the delivery of otherwise impermeable macromolecules. This presents an exciting approach to the treatment of cardiovascular disease (CVD) as a targeted and inherently image-guided therapeutic delivery platform. Objective: The goal of this study is to determine the feasibility of viable US and microbubble mediated delivery of miR-1 to hypertrophic CMs with a view towards reversing the disease. Secondly, we aim to show a correlation between bubble echoes and resulting gene delivery to introduce clinical metrics for the translation of this technique. Methods: CMs were harvested from neonatal rat pups (1-3 days old) and hypertrophied using phenylephrine (100μM). Suspension of healthy or diseased CMs, microbubbles and free miR-1 were placed in a chamber within a 37°C degassed water bath. These samples were insonicated at a mechanical index (MI) ranging from 0.063-0.25 for 2 minutes (20 cycles; 5 kHz PRF) and bubble echoes were recorded via a co-aligned transducer to be processed offline. miR-1 delivery was confirmed with RT-qPCR, cell viablity assesed with MTT, protein expression was measured by immunoblotting and cell size via microscopy. All experiments preformed are at least n=2 independent samples. Result and Conclusion: Treated healthy and diseased CMs demonstrate an upregulation in miR-1 with increasing MI, from 0.063 to 0.188. At MI=0.12, a 2.22 and 1.95-fold increase in miR-1 was shown in diseased and healthy CMs respectively ( p= 0.07, p= 0.02) while maintaining viability (86% and 96% respectively). These miR-1 levels begin to show the reversal of hypertrophy as quantified by increases in target protein expression (1.93-fold in TWF1; 1.38-fold in MEF2A; 1.36-fold in CX43) and cell size decrease (16%, p =0.035) back towards heathy levels. Echo data highlights that relative miR-1 expression positively correlates with bubble disruption ( r =0.76, p =0.04), suggesting a means by which treatment efficiency can be monitored in a clinical setting.In conclusion, we demonstrated that US and microbubbles can be used to successfully delivery miR-1 to CMs, with the potential to reverse the disease phenotype. These findings demonstrate the feasibility of US as an image-guided delivery method for molecular therapeutics in CVD.
Abstract P1082: Activation And Phosphorylation Of Rap1b In The Human Megakaryocytic Leukemia Cell Line DAMI
Authors: Joshua Hetcher, Jaclyn A Wisinski
Journal: Circulation Research (2022)

In platelet-producing megakaryocytes, the signaling protein Rap1b mediates both activation of integrins for cell adhesion and activation of the transcription factor ERK leading to gene expression changes. As a small G-protein, Rap1b acts as a molecular switch with an inactive GDP-bound state and an active GTP-bound state. Additionally, the association of Rap1b within the inner side of the plasma membrane is dictated by cAMP-dependent protein kinase (PKA) phosphorylation. In an unphosphorylated state, Rap1b is attached to the plasma membrane via a lipid anchor. Upon phosphorylation, Rap1b detaches from the membrane and is cytosolic. We hypothesize the location of active Rap1b, dictated by the guanine nucleotide bound (GDP/GTP) and its phosphorylation status, determines which signaling pathways Rap1b contributes to in megakaryocytes. To evaluate this hypothesis, we first need to optimize methods to detect Rap1b activation (GTP binding) and phosphorylation. Using the megakaryocyte cell line (DAMI), we over-expressed green fluorescent protein (GFP)-tagged Rap1b and treated with reagents to stimulate activation or phosphorylation and then use pull-down assays with the Rap binding domain (RBD) to capture activated Rap1b or pan phospho S/T antibodies, respectively. In addition, the activation of downstream proteins like ERK were evaluated in DAMI cells overexpressing GFP-tagged Rap1b phosphorylation mutants. Overall, this work seeks to determine how the spatial distribution of Rap1b, dictated by phosphorylation influences cellular processes.
Abstract P1064: Hippo Signaling Pathway Maintains Sinoatrial Node Homeostasis
Authors: Mingjie Zheng
Journal: Circulation Research (2022)

The sinoatrial node (SAN) functions as pacemaker of the heart to initiate and drive rhythmic heartbeats. The Hippo signaling pathway is a fundamental pathway for heart development and regeneration. Although abnormalities of Hippo pathway are associated with cardiac arrhythmias in human patients, yet its role in the SAN is unknown. We investigated key regulators of the Hippo pathway in the sinoatrial node by conditionally inactivating the Hippo signaling kinases Lats1 and Lats2 using the tamoxifen-inducible, cardiac conduction system (CCS)-specific Cre driver Hcn4 CreERT2 and Lats1 and Lats2 conditional knockout (CKO) alleles. In addition, the Hippo signaling effectors Yap and Taz were conditionally inactivated in the sinoatrial node. To determine the function of the Hippo signaling pathway in the sinoatrial node and other CCS components, we conducted a series of physiological and molecular experiments including telemetry ECG recording, echocardiography, Masson’s Trichrome staining, calcium imaging, immunostaining, Cleavage Under Targets and Tagmentation (CUT&amp;Tag) sequencing using antibodies against Yap1 or H3K4me3, qRT-PCR, and Western blotting. We found that Lats1/2 inactivation caused severe sinoatrial node dysfunction (SND; sick sinus syndrome). Compared to the controls, Lats1/2 CKO mutants exhibited dysregulated calcium handling and increased fibrosis in the sinoatrial node, indicating Lats1/2 function through both cell-autonomous and non-cell-autonomous mechanisms. Notably, the Lats1/2 CKO phenotype was rescued by genetic deletion of Yap and Taz in the CCS, and these rescued mice had normal sinus rhythm and reduced fibrosis of the sinoatrial node, indicating that Lats1/2 function through Yap and Taz . CUT&amp;Tag sequencing data showed that Yap regulates genes critical for calcium homeostasis such as Ryr2 and genes encoding paracrine factors important in intercellular communication and fibrosis induction such as Tgf-β1 and Tgf-β3 . Consistently, Lats1/2 CKO mutants had decreased Ryr2 expression and increased Tgf-β1 and Tgf-β3 expression compared with control mice. We reveal for the first time that the canonical Hippo-Yap pathway has a pivotal role in functional homeostasis of the sinoatrial node. We also provide novel insight into the genetic regulation of sinoatrial node homeostasis and identify new potential therapeutic targets to improve recovery from cardiac arrhythmias.
Response to corticosteroids in chronic airflow obstruction: relationship to emphysema and airways collapse
Authors: DC Weir, RI Gove, AS Robertson, PS Burge
Journal: European Respiratory Journal (1991)

We have studied the relationship between emphysema and airways collapse, and response to corticosteroids in patients with chronic airflow obstruction. One hundred and seven patients completed a placebo-controlled trial comparing 2 wks treatment with oral prednisolone 40 mg.day-1 to inhaled beclomethasone dipropionate 500 micrograms t.d.s. Response to corticosteroids was defined on the basis of changes in forced expiratory volume in one second (FEV1), and/or forced vital capacity (FVC), and/or mean peak expiratory flow (PEF) after treatment. Patients were categorized as those with physiologically defined emphysema (carbon monoxide transfer coefficient (KCO) less than 70% predicted and total lung capacity greater than 120% predicted), and those with pressure dependent airways collapse on the flow-volume loop (ratio of inspiratory to expiratory flow at 50% vital capacity [I:E50] greater than 10). The response to placebo showed a significant order effect, probably due to a carry-over effect of active treatment of at least 3 wks. Hence, the efficacy of active treatment over placebo in the subgroups defined was assessed by analysis of data generated from the first treatment phase of the trial. The presence or absence of physiologically defined emphysema did not affect the response to oral prednisolone. Inhaled beclomethasone dipropionate, however, was less effective in the emphysema group. Pressure dependent airways collapse did not affect the response to either prednisolone or beclomethasone. However, when data from all three treatment phases were analysed there was no significant difference in the response to either drug in any of the subgroups defined.(ABSTRACT TRUNCATED AT 250 WORDS)
Abstract P1098: Atrial Deletion Of AMPK Promotes Atrial Oxidative Stress And The Formation Of Delayed Afterdepolarizations Within The Inter-atrial Pulmonary Vein Junction
Authors: Marine Cacheux, Yina Ma, Xiaohong Wu, Joseph Akar, Lawrence H Young, Fadi G Akar
Journal: Circulation Research (2022)

Atrial specific AMPK deletion leads to spontaneous onset of AF. Electrophysiological mechanisms underlying this heightened propensity remain unknown. We hypothesized that AMPK inactivation forms atrial triggered activity leading to atrial ectopy and AF initiation, in large part, by promoting atrial oxidative stress. Methods: We performed detailed ex vivo atrial optical action potential (AP) mapping on the posterior surface of hearts from mice with atrial deletion of AMPK a1/a2 (AMPK-dKO) (via Cre recombinase driven by sarcolipin) vs littermate controls (Ctrl), both during steady state pacing and following challenge with right atrial stimulus trains designed to promote calcium overload. Mitochondrial (mito) ultrastructure and markers of atrial oxidative stress were measured. To assess the functional impact of atrial oxidative stress, AMPK-dKO mice underwent chronic in vivo treatment with EUK-134 (EUK, 25mg/Kg SQ, 3X/wk) for 16 wks. Results: AMPK-dKO (7/11) but not Ctrl (0/5) hearts exhibited subthreshold delayed afterdepolarizations (DAD) that were consistently localized within a discrete inter-atrial region corresponding with the pulmonary veins (PV) junction. These triggers coincided with atrial oxidative stress indexed by a significant (p&lt;0.05) decrease in GSH/GSSG, PRDX3, SOD2, and increase in nitrotyrosine expression along with atrial mito swelling, decreased count and loss of cristae density. Chronic EUK treatment of AMPK-dKO suppressed the incidence (83% to 40%) and frequency (1.81±0.98/s to 0.083±0.08/s) of PV triggers abrogating the genesis of post-pacing atrial AP ectopy originating from the PV (4/5 vs 0/5). Serial in vivo ECG recordings in a subset of AMPK-dKO mice showed reorganization of the RR vs RR+1 relationship following 16 wks of EUK treatment consistent with decreased incidence of premature atrial complexes. Expression of total and S368 phosphorylated Cx43 were both reduced in the atria of AMPK-dKO mice vs Ctrl and restored by EUK reflecting reversal of pathological molecular remodeling by in vivo ROS scavenging. Conclusions: AMPK deletion promotes formation of left atrial ectopy from DAD sources within the PV region. AMPK plays a central role in the prevention of atrial oxidative stress and associated arrhythmias.
Lobar hypoplasia
Authors: C Della Pona, G Rocco, A Rizzi, M Robustellini, G Rossi, B Crasti
Journal: European Respiratory Journal (1991)

Lung tissue developmental abnormalities are seldom reported. According to the classification of Schneider (1900), which was amended by Boyden (1955), they include pulmonary agenesis, aplasia and hypoplasia. Due to the early onset of symptoms, lung agenesis and aplasia are usually detected soon after birth. Conversely, lung or lobar hypoplasia may remain clinically silent for a long time. A single case of left lower lobe hypoplasia is reported. A recurring and unrelenting septic fever was the presenting symptom, whilst the radiological picture showed a left lower lobe consolidation. On the surgical specimen gross pathology revealed a lobar hypoplasia. At a short-term follow-up (nine months) the patient shows good overall condition, being free from further complications.
Abstract P3087: Single-cell Transcriptomics Reveals Cell-type Specific Transcriptional Responses In Murine Embryonic Hearts Exposed To Maternal Hyperglycemia
Authors: Sathiyanarayanan Manivannan, Corrin R Mansfield, Xinmin Zhang, Madhav Karthik Kodigepalli, Uddalak Majumdar, Vidu Garg, Madhumita Basu
Journal: Circulation Research (2022)

Congenital heart disease (CHD) is a significant pediatric health burden in the United States and a leading non-infectious cause of mortality in the infants. According to CDC, ~1 in 4 babies born with cardiac defects develop critical CHD and require medical interventions during first year of their lives. Despite the strong heritable basis of CHD, genetic variations explain nearly 30% of cases. The phenotypic heterogeneity and incomplete penetrance of the disease implies a vital role of environmental factors as non-genetic contributors of CHD. Women with pregestational diabetes mellitus (PGDM) are about four times more likely to have a pregnancy affected by CHD compared to women without diabetes. Previous studies have established that maternal hyperglycemia (matHG) before pregnancy and in first trimester profoundly increases the risk of CHD among the offspring, with a preponderance of conotruncal and septal defects. However, the cell-type-specific sensitivity to matHG responsible for such cardiac malformations remains unclear. Using a chemically induced murine PGDM model, we first demonstrated increased incidence of CHD in matHG-exposed embryos compared to control (CNTRL) embryos. To evaluate the underlying cellular basis of CHD risk in diabetic pregnancies, we performed in vivo single-cell RNA-sequencing in CNTRL and matHG-exposed embryonic hearts. The transcriptomic data revealed cardiac cell-type-specific molecular changes associated matHG. Bioinformatics analysis showed significant gene expression differences in Isl1+ multipotent progenitor cells, Tnnt2+ cardiomyocytes, Tbx18+ epicardial cells, Sox9+ fibromesenchymal cells, Cdh5+ endocardial/endothelial cells, and in Dlx5+ neural crest cell populations. Pseudotime trajectory analysis suggested HG-induced impairments in genes critical for cardiomyocyte differentiation. Furthermore, in vivo Isl1-derived cell fate mapping studies suggested matHG-mediated perturbations in cardiomyocyte proliferation and differentiation at critical stages of cardiac development. In combination with our scRNA-seq and cell fate mapping data, future mechanistic studies will delineate cell-type-specific gene regulatory network perturbed in matHG environment. Early diagnosis and treatment of diabetes in pregnancy is of great clinical significance and more in-depth studies will enable the development of preventative therapeutic measures to ameliorate PGDM associated CHD.
Abstract P3112: Pharmacological Inhibition Of ATM Sensitizes Rabbit Hearts For Development Of Chronic Anthracycline Cardiotoxicity And Heart Failure
Authors: Olga Lencova, Petra Kollarova, Michaela Adamcova, Yvona Mazurova, Martin Sterba
Journal: Circulation Research (2022)

Introduction: Anthracycline (ANT) cardiotoxicity is still a serious complication of cancer chemotherapy. While it has been originally explained by direct oxidative damage to the heart, recently topoisomerase II beta (TOP2B)-dependent DNA damage to cardiomyocytes has been implicated. However, the specific role of DNA damage response (DDR) signaling downstream of TOP2B in the development of chronic ANT cardiotoxicity remains unclear. Hypothesis: Pharmacological inhibition of ATM will confirm the involvement of the ATM pathway in DDR signaling in the heart after ANT exposure and determine whether this signaling leads to the development of ANT cardiotoxicity or the opposite is true. Methods: A well-established rabbit model of chronic ANT cardiotoxicity (daunorubicin/DAU/3 mg/kg, weekly for ten weeks) was employed. The highly selective ATM inhibitor AZD0156, which is currently in clinical evaluation elsewhere, was administered at 0.5 mg/kg before each DAU dose. The results were compared with the group receiving AZD0156 alone and the controls receiving saline or vehicle for AZD0156. In another set of animals, the acute DDR in the heart was studied 6 hours after a single administration of the same drugs. Results: AZD0156 effectively prevented acute DAU-induced increase of p53 levels and up-regulation of p53 target genes (p21 and many others) in the left ventricular myocardium. Chronic co-treatment of AZD0156 with DAU markedly increased the incidence of DAU-induced blood congestion (hydrothorax 80 % vs. 40 % in the DAU-alone group), end-stage heart failure, and heart failure-related mortality (60 % vs. 20 % in the DAU-alone group). Before the observed deaths, plasma levels of cardiac troponin T increased steeply, while left ventricular fractional shortening (LVFS) determined by echocardiography declined. The last measured LVFS values in the AZD0156+DAU group were significantly lower than in the DAU-alone group. AZD0156 alone was well tolerated and had no significant impact on any studied parameter. Conclusion: ANT-induced DDR signaling in the heart appears to be ATM-dependent, and pharmacological inhibition of ATM sensitizes rabbit hearts to ANT-induced chronic cardiotoxicity and heart failure.
Congenital 6‐phosphogluconate dehydrogenase (6PGD) deficiency associated with chronic hemolytic anemia in a Spanish family
Authors: J. Ll. Vives Corrons, D. Colomer, A. Pujades, A. Rovira, M. Aymerich, A. Merino, J. Ll. Aguilar i Bascompte
Journal: American Journal of Hematology (1996)